Heating and ventilating system for aircraft



M. G. BEARD Aug. 11, 1936.

HEATING AND VENTILATING SYSTEM FOR AIRCRAFT Filed March 25, 1952 2 Sheets-Sheet 1 INVENTOR flym/z 5 Zara M M A'ITORNEYS Aug. 11, 1936. M. e. BEARD HEATING AND VENTILATING SYSTEM FOR AIRCRAFT 2 Sheets-Sheet 2 Filed March 23, 1.9.32

INVENTOR Myron fi .Bzard @M 4 ATTORNEYS Patented Aug. 11, 1936 HEATING AND VENTILATING SYSTEM FOR AIRCRAFT Myron G. Beard, Farmingdale, N. Y., assignor,

by mesne assignments, to Curtiss Aeroplane &

Motor Company, Inc.

Application March 23, 1932, Serial No. 600,620

8 Claims.

This invention relates in general to heating and ventilating systems for closed motor vehicles and more particularly to such a system which will be especially adapted for aircraft cabins.

An object of the invention is to provide a system wherein a steady ingress of fresh air is uniformly heated by the engine exhaust gases prior to its entrance into the cabin. Another object is to provide a system in which a vapor is the medium of heat exchange and in which the heating of the air is determined by means which automatically regulate the pressure of the vapor in the system within predetermined limits.

Another object of the invention is to provide in such a system automatic means whereby its operation is prevented below predetermined adjustments of the throttle of the engine and manual means for shutting down the system both above and below the said throttle adjustment limits.

A further object is to provide a heating sys tem wherein the heating effect of a circulating vapor being heated by the exhaust gases of the engine may be automatically and manually regulated by combined pressure, engine throttle, and manual control device.

The general arrangement and purposes of the system is similar in nature to that described in my copending application for patent for improvements in Heating and ventilating system, Ser. No. 559,921, filed August 28, 1931 with ex-- ception that the present system utilizes vapor as the heat transfer medium from the exhaust manifold to the radiator through which the inrushing fresh air passes to the cabin interior. With the foregoing and other objects in view, the invention consists in the combination of parts and in the details of construction hereinafter set forth in the following specification and appended claims, certain embodiments thereof being illustrated in the accompanying drawings in which Fig. 1 is a diagrammatical View in perspective of the device.

Fig. 2 is a view in side elevation of the airplane partly in section showing the system installed.

Figure 3 is an enlarged sectional view taken through the valve casing.

Referring-more particularly to the drawings there is provided a storage tank I for water or other liquid having communicating tubes 2, 3, and 4 to a series of heating coils 5 arranged in the exhaust stack I! from the engine 24. These coils act as flash boilers in.that the liquid is not-admitted to the coils until they are sufficiently heated by the exhaust gases to immediately vaporize the liquid when admitted. The

vapor thus created is delivered through the tubes 6 and I to a radiator 8 of honeycomb multicellular or other suitable construction.

The conduit 9 preferably extends forwardly to a point such as 22 preferably in the leading edge of the wing 23 so as to provide an inlet for fresh air. The radiator 8 is also preferably arranged ahead of the firewall of the conventional cabin airplane fuselage construction and so as to be substantially directly above the heating coils. The inrushing air in conduit 9 strikes and passes through the radiator and the consequent heat exchange between such air and the steam vapor in the radiator results in the heating of the ventilating air and the condensation of the vapor in the radiator. The condensed vapor flows through pipe 10 back into the liquid storage tank. The ventilating air thus heated may be carried by the conduit H to suitable registers within the cabin.

The system is provided with the usual safety devices such as a steam pressure relief valve l3 with a blow off conveying tube l4 and there is preferably provided a steam pressure gauge, the connection to which is indicated at l5. All of the tubes of the system are preferably made of stainless steel. The storage tank may be provided with a filler cock I6 and a vent cock I! to insure filling with liquid and the absence of air.

As above stated the heating coils are heated by the exhaust gases prior to admitting water thereinto by the operation of the manually operated shut off valve [8. The object is to never have the heating coils filled with liquid but on the contrary to have such liquid rapidly vaporized into steam upon interior contact therewith. Such vapor, as above stated, becomes condensed in the radiator and the condensate flows back into the storage tank completing the cycle of circulation.

A thermometer l9 may be attached to the stor age tank to indicate the temperature of the condensate. The flow of the condensate into the heating coils when the cock I8 is open is regulated by a valve 20 which is in the nature of an automatic shut off valve controlled both by the steam pressure and manually by the carburetor throttle. Thus the steam pressure relief valve l3 may be set to open at 50 pounds pressure and the regulating valve in a valve casing 20 so set buretor throttle 25 such as the conventional push pull wire 26 extending around a pulley 21 so that the valve will be closed when the throttle is less than one third open or some other set limit. In this particular the throttle connection is controlling as to the regulation of the valve but when the throttle is more than one third open the pressure within the system controls the operation of the valve and the consequent regulation of liquid flow into the coils. This prevents the accumulation of water in the coils and leaves them sufliciently hot to vaporize the liquid practically instantaneously with its entry thereinto and also prevents the steam pressure from rising above the safety point. Thus the main function of the pressure relief valve 3 is that of relieving pressure in the event of failure of the automatic valve 20 or in the event of a superfluous accumulation of water which might otherwise occur in the heating coils either prior to or during the actual use of the system as a heating unit.

This is brought about by the use of a valve 20' in the valve casing 20 provided with a stem 28 slidable in a recess 29 and operatively connected to the crank 2| so that the valve may be moved toward and away from its seat 30. Arranged below the valve 20' is the piston 3| adapted to be spring-pressed downwardly toward the lower end of the cylinder 32 by means of a compression spring 33, positioned about the stem or rod 34 which rigidly connects the valve 20' with the piston 3|. A vent opening 36 is provided in the side of the cylinder 32 to maintain the air in the cylinder above the piston 3| at atmospheric pressure and to prevent a vacuum or pressure to be caused by the movement of the piston within the cylinder. The elbow connection provides for the passage of the liquid from the lower portion of the valve casing 20 to the space beneath the piston 3| and thence into'the pipe 3. When the valve I8 is opened, communication is established between the lower portion of the valve 20 and the heating coils 5. When the engine throttle 25 is opened to a predetermined point, the members 2|, 26, and 21 of the valve operating mechanism function to cause the opening of valve 20' which permits the liquid to flow by gravity from the storage receptacle I through the pipe 2, and the valves 20 and I8 and pipes 3 and 4 into the heating coils 5 where it is converted into steam or vapor with a resulting increase in pressure within the system. When this pressure exceeds a predetermined amount, for which the spring 33 is designed or adjusted, it exerts a force on the lower side of the piston 3| which overcomes the opposition of the spring 33, causing the piston 3|,

' rod 34 and valve 20 to move upwardly as a unit and to cause the valve 20' to close tight against its seat 30, thereby shutting off the flow of the liquid to the heating coils 5 and causing reduction of the pressure within the system. The members 2|, 26 and 21 of the throttle actuating mechanism prevent the engine throttle setting from being affected by the closing of the valve 20 due to the pressure actuating means. Assuming that the throttle remains opened to the predetermined extent, a reduction of pressure within the system will permit the spring 33 to open the valve 20' and restore the flow of liquid again to the heating coils 5.

I claim:

1. In combination with an internal combustion engine having a conveyor for the exhaust gases, a circulating system including heating coils subjected to the heat of said gases, a vapor condensing radiator, a liquid storage container in communication with said radiator and said coils, manually controlled valve means for regulating the flow of liquid into said coils, automatic valve means arranged between and in communication with said storage cpntainer and said coils and under engine throttle control for regulating a liquid flow from said container to said coils when said manual valve is open, said automatic valve means being opened when said throttle control is opened a predetermined amount, and being further adapted to be automatically operated by the pressure within the heating coils of the circulating system so as to close such valve when the pressure exceeds a predetermined amount, and to open said valve when the pressure within the circulating system becomes less than such amount.

2. In combination with. an internal combustion engine having a conveyor for-the exhaust gases, a circulating vapor heating system including heat ing coils subjected exteriorly to the heat of said gases, a vapor condensing radiator, a liquid storage container in communication with said radiator and said coils, means arranged between and in communication with said container and said-- coils for insuring against the undesired accumulation of liquid in said coils in excess of their capacity to accomplish the instantaneous vaporization thereof, said means including a manually controllable valve for controlling a liquid fiow from said container to said coils and an automatic valve, the opening of which is restricted by mechanical means associated with the throttle of the said engine, the said automatic valve being adapted to be opened by decrease in pressure within the said heating coils below a predetermined amount within limits established by the setting of the said engine throttle and to be closed automatically when the pressure within the heating coils exceeds a predetermined amount.

3. In combination in an internal combustion engine propelled closed vehicle, a heating and ventilating system including conveyors for the ingress of air into the compartment, and a circulating vapor system for heating said air prior to its entry into said compartment, said system including a radiator through which the air passes, a liquid storage container for collecting the condensate from said radiator, heating coils arranged so as to be exposed to the heat of the exhaust gases of said engine, valve means between said container and said coils to regulate the flow of liquid into the latter, said valve means being controllable in response to the operation of said engine, being opened by the opening of the throttle of said engine beyond a predetermined setting and when open being automatically controllable by the steam pressure generated in the coils and steam conveying pipes between said coils and said radiator such that the said valve means is caused to be closed by an increase in said steam pressure beyond a predetermined amount.

4. In combination in an internal combustion engine propelled closed vehicle, a heating and ventilation system including conveyors for the ingress of air into the compartment, and a circulating vapor system with a radiator for heating said air prior to its entry into said compartment and for condensing said vapor, said system including a liquid storage container and a series of heating coils subjected to the heat of the engine exhaust gases, and valve means for regulating the fiow of liquid into said coils, the said valve means being opened and closed automatically in response to decrease and increase respectively of 76 engine propelled closed vehicle, a heating and ventilation system including conveyors for the ingress of air into the compartment, and a circulating vapor system with a radiator for heating said air prior to its entry'into said compartment and for condensing said vapor, wid system including a. liquid storage container and a series of heating coils subjected to the heat of the engine exhaust gases, and valve means for regulating the flow of liquid into said coils, said valve means being closed and opened directly in response to pressure increase and decrease respectively within the said circulating system, and the said valve means being closed and opened when the throttle of the said engine is correspondingly adjusted below or above a predetermined amount.

6. In a circulating system for heating the interior of an aircraft cabin, the combination with a vapor generator associated with the exhaust of the aircraft engine, a vapor condensing radiator, and a storage receptacle adapted to receive the condensate from the said radiator and to circulate the same to the said vapor generator, of means for limiting the circulation from the storage receptacle to said generator directly as the said engine is throttled down to a predetermined setting and directly limited in response to pressure increase within the portion of the circulating system between the said storage receptacle and said generator.

'7. In a circulating system for. heating the inte rior of an aircraft cabin, the combination with a. vapor generator associated with the exhaust of the aircraft engine, a vapor condensing radiator, and a storage receptacle adapted to receive the 5 condensate from the said radiator and to circulate the same to the said vapor generator, of means for controlling the circulation within that portion of the system between the said storage receptacle and said generator such that as the throttle setting of the said engine is moved below a predetermined position the said circulation is arrested, the said circulation controlling means being opened and closed in response to decrease in the system at all other settings of the said engine throttle above the said predetermined position.

8. In a circulating system for heating the interior of an aircraft cabin, the combination with a vapor generator associated with the exhaust of the aircraft engine, a vapor condensing radiator, and a storage receptacle adapted to receive the condensate from the said radiator and to circulate the same to the said vapor generator, of means for controlling the circulation within that portion of the system between the said storage receptacle and said generator, such that as the throttle of said engine is set beyond a predetermined point the said means permits circulation within the said portion of the system, thesaid controlling means being adapted to increase or diminish the said circulation directly in response to a respective decrease or increase in pressure within the said portion of the system.

MYRON G. BEARD. 

